1. Field of the Invention
The present invention relates to monoclonal antibodies specifically binding to a membrane antigen of human mesenchymal stem cells, hybridoma cell lines producing the same, and methods for identifying or isolating human mesenchymal stem cells using the same.
2. Description of the Related Art
Hemopoiesis is sustained by two main cellular components, hematopoietic cells and mesenchymal stem cells (MSCs).(1,2) MSCs are multipotent and are the precursors of marrow stroma, bone, cartilage, muscle and connective tissue. MSCs isolated from bone marrow have been shown to have multilineage potential and have been utilized experimentally in cell-based therapies.(3,4) Human bone marrow (BM) has been shown to contain MSCs that fabricate the connective tissue network of the marrow, called the stroma.(5) MSCs may have an important role in the repair of musculoskeletal tissues, and can differentiate into osteoblasts,(6) chondrocytes,(7) adipocytes,(3) tenocytes,(8) and myocytes.(9) Although MSCs are present in very small numbers in the bone marrow, they are capable of substantial proliferation and expansion in culture.(10,11) Undifferentiated MSCs exhibit a fibroblast-like morphology and have a characteristic pattern of cell-surface antigen expression.(12) the present invention we developed methods for isolating and culturing MSCs from human bone marrow aspirates and found that these cultured cells display a fibroblastic morphology and retain their pluripotentiality following extensive culture expansion.(13,14) MSCs are characterized phenotypically in humans as non-hematopoietic cells, since they do not express CD34 or CD45.(3) Characteristic markers for expanded MSCs have been reported and designated as SH2, SH3, and SH4.(15) However, none of these markers are specific for MSCs, which hampers the isolation of pure MSC populations. In addition, there are no antibodies specifically bound to MSCs.
Throughout this application, various patents and publications are referenced and citations are provided in parentheses. The disclosure of these patents and publications in their entities are hereby incorporated by references into this application in order to more fully describe this invention and the state of the art to which this invention pertains.